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Properties, uses and differences between copper, brass, bronze and white copper

November 1, 2023

Pure copper is a purple-red metal, commonly known as red copper, red copper or red copper. Pure copper is highly malleable. Pure copper the size of a drop of water can be stretched into filaments up to two kilometers long, or rolled into almost transparent foils larger than a bed. The most valuable property of pure copper is its very good electrical conductivity, second only to silver among all metals, so it has become the protagonist of the electrical industry.


Pure copper has much wider uses than pure iron. Every year, 50% of copper is electrolytically purified into pure copper and used in the electrical industry. The pure copper mentioned here must be very blunt indeed, containing more than 99.95% copper. Very small amounts of impurities, especially phosphorus, arsenic, aluminum, etc., can greatly reduce the conductivity of copper. The oxygen contained in copper (a small amount of oxygen is easily mixed during copper smelting) has a great influence on the conductivity. Copper used in the electrical industry must generally be oxygen-free copper. In addition, impurities such as lead, antimony, and bismuth will prevent the copper crystals from being combined together, causing thermal brittleness and affecting the processing of pure copper. This kind of very pure copper is generally refined by electrolysis: impure copper (i.e. blister copper) is used as the anode, pure copper is used as the cathode, and copper sulfate solution is used as the electrolyte. When current passes through, the impure copper on the anode gradually melts, and pure copper gradually precipitates on the cathode. The copper refined in this way has a purity of up to 99.99%.


Red copper is a relatively pure type of copper. It can generally be considered as pure copper. It has good electrical conductivity and plasticity, but poor strength and hardness.


Properties and uses of brass:


Brass is a kind of copper containing other alloy components. It is cheaper than copper. Its electrical conductivity and plasticity are slightly worse than that of copper, but its strength and hardness are higher.


Brass is an alloy of copper and zinc. The simplest brass is a copper-zinc binary alloy, called simple brass or ordinary brass. Brass with different mechanical properties can be obtained by changing the zinc content in the brass. The higher the zinc content in brass, the higher its strength and slightly lower plasticity. The zinc content of brass used in industry does not exceed 45%. Any higher zinc content will cause brittleness and deteriorate the properties of the alloy. Adding 1% tin to brass can significantly improve the brass's ability to resist seawater and marine atmosphere corrosion, so it is called navy brass. Tin can improve the cutting performance of brass. Lead brass is what we usually call easy-cut national standard copper. The main purpose of adding lead is to improve the cutting processability and wear resistance. Lead has little effect on the strength of brass. Engraved copper is also a type of lead brass. Most brass has good color, processability, ductility, and is easy to be electroplated or painted.


In industry and civil use, different materials are selected according to different usage characteristics. If you want to make wires, they need to be softer, so copper is better. For connecting parts, brass is often used for screws.


Properties and uses of bronze:


Originally referred to as copper-tin alloy, later copper alloys other than brass and white copper were called bronze, and the name of bronze was often preceded by the name of the first major added element. Tin bronze has good casting properties, good friction reduction properties and good mechanical properties, and is suitable for manufacturing bearings, worm gears, gears, etc. Lead bronze is a widely used bearing material in modern engines and grinding machines. Aluminum bronze has high strength, good wear resistance and corrosion resistance, and is used to cast high-load gears, bushings, marine propellers, etc. Beryllium bronze and phosphor bronze have high elastic limit and good electrical conductivity, and are suitable for manufacturing precision springs and electrical contact components. Beryllium bronze is also used to manufacture non-sparking tools used in coal mines, oil depots, etc.


Properties and uses of white copper:


Copper alloy with nickel as the main added element. The copper-nickel binary alloy is called ordinary cupronickel; the cupronickel alloy with additions of manganese, iron, zinc, aluminum and other elements is called complex cupronickel. Industrial white copper is divided into two categories: structural white copper and electrical white copper. Structural white copper is characterized by good mechanical properties and corrosion resistance, and beautiful color. This kind of white copper is widely used in the manufacture of precision machinery, chemical machinery and ship components. Electrical white copper generally has good thermoelectric properties. Manganese copper, constantan, and kaotan are manganese-nickel copper with different manganese contents. They are materials used in manufacturing precision electrical instruments, varistors, precision resistors, strain gauges, thermocouples, etc.


How to distinguish copper, brass, bronze and white copper:


White copper, brass, red copper (also called red copper), and bronze (green gray or grayish yellow) are distinguished by color. Among them, white copper and brass are easy to distinguish; red copper is pure copper (impurities <1%), Bronze (about 5% of other alloy components) is slightly difficult to distinguish. When not oxidized, the color of red copper is brighter than bronze, and bronze is slightly cyan or yellowish and darker; after oxidation, red copper turns black, and bronze is greenish (harmful oxidation of too much water) or chocolate color.